There are no extra enemies in US version. It's the same amount as BK3. In fact, few enemies were removed in SoR3. Broke balance? It gives you all the tools and opportunities to defeat enemies and win the game. It all comes down to how you play the game: behaving with enemies, handling your character and knowing efficient strats. Aside some annoying bugs that mess you up here and there, it's all on the player whether he gets wrecked or succeeds. US is just tougher and requires good skill at the game. JP one is piss easy and barely presents any real challenge to the player. If that's what you prefer to consider balance...